Re: [Intel-gfx] [PATCH 1/8] drm/i915: Added is_intel_rpm_allowed helper

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Thu, Jul 21, 2022 at 03:29:48PM +0530, tilak.tangudu@intel.com wrote:
> From: Tilak Tangudu <tilak.tangudu@intel.com>
> 
> Added is_intel_rpm_allowed function to query the runtime_pm
> status and disllow during suspending and resuming.

> 
> v2: Return -2 if runtime pm is not allowed in runtime_pm_get
> and skip wakeref release in runtime_pm_put if wakeref value
> is -2. - Jani N

Should we have some defines instead of the -#s?

> Signed-off-by: Tilak Tangudu <tilak.tangudu@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_runtime_pm.c | 23 ++++++++++++++++++++++-
>  drivers/gpu/drm/i915/intel_runtime_pm.h |  1 +
>  2 files changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 6ed5786bcd29..704beeeb560b 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -113,7 +113,7 @@ static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
>  	unsigned long flags, n;
>  	bool found = false;
>  
> -	if (unlikely(stack == -1))
> +	if (unlikely(stack == -1) || unlikely(stack == -2))
>  		return;
>  
>  	spin_lock_irqsave(&rpm->debug.lock, flags);
> @@ -320,6 +320,21 @@ untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
>  }
>  
>  #endif
> +static int intel_runtime_pm_status(struct intel_runtime_pm *rpm)
> +{
> +	return rpm->kdev->power.runtime_status;
> +}
> +
> +bool is_intel_rpm_allowed(struct intel_runtime_pm *rpm)

why not static?

> +{
> +	int rpm_status;
> +
> +	rpm_status = intel_runtime_pm_status(rpm);
> +	if (rpm_status == RPM_RESUMING

I don't have a good feeling about this. If we are resuming we shouldn't
grab extra references... This seems a workaround for the lock mess.

> || rpm_status == RPM_SUSPENDING)

and when we are suspending and we call this function is because we need
to wake up, no?!

> +		return false;
> +	else
> +		return true;
> +}
>  
>  static void
>  intel_runtime_pm_acquire(struct intel_runtime_pm *rpm, bool wakelock)
> @@ -354,6 +369,9 @@ static intel_wakeref_t __intel_runtime_pm_get(struct intel_runtime_pm *rpm,
>  						     runtime_pm);
>  	int ret;
>  
> +	if (!is_intel_rpm_allowed(rpm))
> +		return -2;
> +
>  	ret = pm_runtime_get_sync(rpm->kdev);
>  	drm_WARN_ONCE(&i915->drm, ret < 0,
>  		      "pm_runtime_get_sync() failed: %d\n", ret);
> @@ -490,6 +508,9 @@ static void __intel_runtime_pm_put(struct intel_runtime_pm *rpm,
>  
>  	untrack_intel_runtime_pm_wakeref(rpm, wref);
>  
> +	if (wref == -2)
> +		return;
> +
>  	intel_runtime_pm_release(rpm, wakelock);
>  
>  	pm_runtime_mark_last_busy(kdev);
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.h b/drivers/gpu/drm/i915/intel_runtime_pm.h
> index d9160e3ff4af..99418c3a934a 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.h
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.h
> @@ -173,6 +173,7 @@ void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
>  void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
>  void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
>  void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
> +bool is_intel_rpm_allowed(struct intel_runtime_pm *rpm);

if really need to export please follow the naming convention.\

>  
>  intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
>  intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
> -- 
> 2.25.1
>